On Tue, Apr 23, 2019 at 08:30:55PM +0200, David Hildenbrand wrote: > On 23.04.19 12:01, Daniel P. Berrangé wrote: > > On Tue, Apr 23, 2019 at 11:54:53AM +0200, Philippe Mathieu-Daudé wrote: > >> Hi Richard, Daniel, > >> > >> On 4/17/19 7:32 AM, Richard Henderson wrote: > >>> If one uses -L $PATH to point to a full chroot, the startup time > >>> is significant. In addition, the existing probing algorithm fails > >>> to handle symlink loops. > >>> > >>> Instead, probe individual paths on demand. Cache both positive > >>> and negative results within $PATH, so that any one filename is > >>> probed only once. > >>> > >>> Use glib filename functions for clarity. > >>> > >>> Signed-off-by: Richard Henderson <richard.hender...@linaro.org> > >>> --- > >>> util/path.c | 211 ++++++++++++++-------------------------------------- > >>> 1 file changed, 57 insertions(+), 154 deletions(-) > > > > > >>> +#if GLIB_CHECK_VERSION(2, 58, 0) > >> > >> Should we raise GLIB_VERSION_MAX_ALLOWED in "glib-compat.h"? > >> > >> Currently it is: > >> > >> /* Ask for warnings if code tries to use function that did not > >> * exist in the defined version. These risk breaking builds > >> */ > >> #define GLIB_VERSION_MAX_ALLOWED GLIB_VERSION_2_40 > > > > Use of 2.40 is set in accordance with our targetted platform support > > policy. If Peter has stopped using the Ubuntu 14.04 build host, we > > could bump it to 2.42. Once our dev tree opens up we could in fact > > drop Jessie since we'll be supporting Buster by the time next QEMU > > is released. That would still only take us upto perhaps Glib 2.48 > > > > Glib 2.58 is waaaay to new to rely on. > > > > commit e7b3af81597db1a6b55f2c15d030d703c6b2c6ac > > Author: Daniel P. Berrangé <berra...@redhat.com> > > Date: Fri May 4 15:34:46 2018 +0100 > > > > glib: bump min required glib library version to 2.40 > > > > Per supported platforms doc[1], the various min glib on relevant > > distros is: > > > > RHEL-7: 2.50.3 > > Debian (Stretch): 2.50.3 > > Debian (Jessie): 2.42.1 > > OpenBSD (Ports): 2.54.3 > > FreeBSD (Ports): 2.50.3 > > OpenSUSE Leap 15: 2.54.3 > > SLE12-SP2: 2.48.2 > > Ubuntu (Xenial): 2.48.0 > > macOS (Homebrew): 2.56.0 > > > > This suggests that a minimum glib of 2.42 is a reasonable target. > > > > The GLibC compile farm, however, uses Ubuntu 14.04 (Trusty) which only > > has glib 2.40.0, and this is needed for testing during merge. Thus an > > exception is made to the documented platform support policy to allow for > > all three current LTS releases to be supported. > > > > Docker jobs that not longer satisfy this new min version are removed. > > > > [1] https://qemu.weilnetz.de/doc/qemu-doc.html#Supported-build-platforms > > > > Reviewed-by: Thomas Huth <th...@redhat.com> > > Signed-off-by: Daniel P. Berrangé <berra...@redhat.com> > > > > > >> > >> From commit e71e8cc035558eabd6b3e19f6d3254c754c027ef: > >> > >> glib: enforce the minimum required version and warn about old APIs > >> > >> There are two useful macros that can be defined before including > >> glib.h that are related to the min required glib version > >> > >> - GLIB_VERSION_MIN_REQUIRED > >> > >> When this is defined, if code uses an API that was deprecated > >> in this version, or older, a compiler warning will be emitted. > >> This alerts maintainers to update their code to whatever new > >> replacement API is now recommended best practice. > >> > >> - GLIB_VERSION_MAX_ALLOWED > >> > >> When this is defined, if code uses an API that was introduced > >> in a version that is newer than the declared version, a compiler > >> warning will be emitted. This alerts maintainers if new code > >> accidentally uses functionality that won't be available on some > >> supported platforms. > >> > >> The GLIB_VERSION_MAX_ALLOWED constant makes it a bit harder to opt > >> in to using specific new APIs with a GLIB_CHECK_VERSION conditional. > >> To workaround this Pragmas can be used to temporarily turn off the > >> -Wdeprecated-declarations compiler warning, while a static inline > >> compat function is implemented. This workaround is illustrated with the > >> implementation of the g_strv_contains method to satisfy the test suite. > >> > >>> + base = g_canonicalize_filename(prefix, NULL); > >>> +#else > >>> + if (prefix[0] != '/') { > >>> + char *cwd = g_get_current_dir(); > >>> + base = g_build_filename(cwd, prefix, NULL); > >>> + g_free(cwd); > >>> + } else { > >>> + base = g_strdup(prefix); > >>> + } > >>> +#endif > > > > To use functionality from newer glib releases we can't put the #ifdef > > conditionals inline in the main source files. > > > > They have to be put into glib-compat.h instead. There's a detailed > > comment in that file illustrating how todo this without triggering > > the compile warnings about deprecations. > > > > > > Regards, > > Daniel > > > > Trying to build (Richard's tcg-vec-next branch) on Fedora29 I get > > util/path.c: In function 'init_paths': > util/path.c:24:5: error: 'g_canonicalize_filename' is deprecated: Not > available before 2.58 [-Werror=deprecated-declarations] > base = g_canonicalize_filename(prefix, NULL); > ^~~~
[snip] This is exactly why the compat code needs to go into glib-compat.h. There is a special mechanism in that file for avoiding triggering the deprecation warnings from glib. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
